US20130192619A1 - Electronic cigarette and method - Google Patents

Abstract

An electronic smoking article includes an outer tube extending in a longitudinal direction, an inner tube within the outer tube and including a pair of opposing slots, a liquid supply comprising a liquid material, a coil heater, a wick and a mouth end insert. The coil heater is located in the inner tube. The coil heater is formed of an iron-free, nickel-chromium alloy and has substantially uniformly spaced windings. The wick is surrounded by the coil heater such that the wick delivers liquid material to the coil heater and the coil heater heats the liquid material to a temperature sufficient to vaporize the liquid material and form an aerosol in the inner tube.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/593,004, filed on Jan. 31, 2012, the entire content of which is incorporated herein by reference thereto.
SUMMARY OF SELECTED FEATURES
• An electronic cigarette or cigar (collectively “smoking article”) is provided which includes a heater element which vaporizes liquid material to produce an aerosol or “vapor”. The heater element preferably comprises a resistive heater coil, with a wick extending therethrough. The heater coil is constructed in a manner and formed from a material such that the production of hot spots and excessive temperatures are avoided during a puff.
• The electronic article preferably includes a mouth end insert that includes at least two, diverging outlets to impart a fuller mouthfeel from the vapor output. Preferably, the aforementioned multi-ported mouth end insert cooperates with a gasket. Upon being drawn through the gasket, the vapor output enters a space just upstream of the mouthpiece which allows the air stream to expand and decelerate before entering the passages of the mouth piece insert so as to substantially avoid perceptions of “hot” at or about the lips of the “smoker”.
• The electronic article preferably includes a metal case portion and a precision-formed primary, air inlet port at a location along the metal case portion, preferably along a metal side wall portion of the article. The air inlet port is precision-formed within close tolerances and the air inlet port is sized so as to be the predominating source of pressure drop along an air pathway of communication between the air inlet and the source of vapor (the heater). Such arrangement assures that RTD remains essentially the same from one puff to the next and from one article to the next. To further enhance consistent performance, RTD of an article is checked in the course of its manufacture, and corrective measure undertaken, if necessary.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a top planar view of an electronic cigarette according to a first embodiment;
• FIG. 2 is a side cross-sectional view of the electronic cigarette shown inFIG. 1;
• FIG. 3ais an exploded, perspective view of elements comprising the cartridge section of the electronic cigarette shown inFIG. 1;
• FIG. 3bis a detailed view of an air inlet port of the cartridge section of the electronic cigarette shown inFIG. 1;
• FIG. 4 is a perspective view of the mouth end insert of the electronic cigarette shown inFIG. 1;
• FIG. 5 is a cross-sectional view along line A-A of the mouth end insert ofFIG. 4;
• FIG. 6 is a perspective view of an alternative embodiment of the mouth end insert of the electronic cigarette shown inFIG. 1;
• FIG. 7 is a cross-sectional view along line B-B of the mouth end insert ofFIG. 6;
• FIG. 8 is an enlarged detail view of the heater assembly of the electronic cigarette shown inFIG. 1;
• FIG. 9A is an enlarged view of the inner tube with a heater coil and wick assembly in position prior to positioning of a closure ring;
• FIG. 9B is an enlarged view of the inner tube with a heater coil and wick assembly in position after positioning of a closure ring;
• FIG. 10 is a cross-sectional view of a third embodiment of a mouth end insert for use with the electronic cigarette ofFIG. 1;
• FIG. 11 is an exploded view of the mouth end insert ofFIG. 10;
• FIG. 12 is a detailed view of an alternative connection arrangement assembly for use with the electronic cigarette ofFIG. 1; and
• FIG. 13 is a second embodiment of a connector cathode including a notch.
• FIGS. 14A,14B and14C illustrate a third embodiment of a connector cathode including angled holes.
• FIG. 15 is an illustration of a connector cathode and anode in which the anode is shortened to allow communication with air inlets.
• FIG. 16 is a top view of an electronic cigarette including an aroma strip on an outer surface thereof.
• FIG. 17 is a perspective view of a fourth embodiment of a mouth end insert for use with the electronic cigarette.
• FIG. 18 is a cross-sectional view of an electronic cigarette according to the first embodiment and further including a sleeve assembly.
• FIG. 19 is a side-view of an electronic cigarette according to another embodiment.
DETAILED DESCRIPTIONElectronic Cigarette Layout
• Referring toFIGS. 1 and 2, a novel electronic cigarette (article)60 is provided and comprises a replaceable cartridge (or first section)70 and a reusable fixture (or second section)72, which in the preferred embodiment are coupled together at a threadedconnection205 or by other convenience such as a snug-fit, detent, clamp and/or clasp. Generally, thesecond section72 includes apuff sensor16 responsive to air drawn into thesecond section72 via anair inlet port45 adjacent the free end or tip of thecigarette60, abattery1 and control circuitry. The disposablefirst section70 includes a liquid supply region of22 of liquid and aheater14 that aerosolizes liquid that is drawn from theliquid supply region22 through awick28. Upon completing the threadedconnection205, thebattery1 is connectable with theelectrical heater14 of thefirst section70 upon actuation of the puff sensor. Air is drawn primarily into thefirst section70 through one ormore air inlets44.
• In the preferred embodiment, once the liquid of the cartridge is spent, only thefirst section70 is replaced. An alternate arrangement includes a layout where theentire article60 is disposed once the liquid supply is depleted. In such case the battery type and other features might be engineered for simplicity and cost-effectiveness, but generally embodies the same concepts as in the preferred embodiment in which the second section is reused and/or recharged.
• In a preferred embodiment, theelectronic cigarette60 is about the same size as a conventional cigarette. In some embodiments, theelectronic cigarette60 can be about 80 mm to about 110 mm long, preferably about 80 mm to about 100 mm long and about 7 mm to about 8 mm in diameter. For example, in a preferred embodiment, the electronic cigarette is about 84 mm long and has a diameter of about 7.8 mm.
• Preferably, at least one adhesive-backed label is applied to theouter tube6. The label completely circumscribes theelectronic cigarette60 and can be colored and/or textured to provide the look and/or feel of a traditional cigarette. The label can include holes therein which are sized and positioned so as to prevent blocking of theair inlets44.
• Theouter tube6 and/or theinner tube62 may be formed of any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK), ceramic, and polyethylene. Preferably, the material is light and non-brittle.
Cartridge Structure
• Referring now toFIGS. 1,2 and3 thefirst section70 includes an outer tube (or casing)6 extending in a longitudinal direction and an inner tube (or chimney)62 coaxially positioned within theouter tube6. Preferably, a nose portion61 (seeFIG. 3a) of an upstream gasket (or seal)15 is fitted into anupstream end portion65 of theinner tube62, while at the same time, anouter perimeter67 of thegasket15 provides a liquid-tight seal with an interior surface of theouter casing6. Theupstream gasket15 also includes a central,longitudinal air passage20, which opens into an interior of theinner tube62 that defines acentral channel21. Atransverse channel33 at a backside portion of thegasket15 intersects and communicates with thecentral channel20 of thegasket15. Thischannel33 assures communication between thecentral channel20 and a space35 (seeFIG. 2) defined between thegasket15 and acathode connector piece37. In the preferred embodiment, thepiece37 includes a threaded section for effecting the threadedconnection205.
• Thecathode connector piece37 includesopposing notches38,38′ about itsperimeter39, which, upon insertion of thecathode connector piece37 into thecasing6, are aligned with the location of each of two RTD-controlling,air inlet ports44 and44′ in theouter casing6. In an embodiment, such alignment may appear as shown in FIG.3′ (Detail). Such arrangement allows for placement of theports44,44′ close to the threadedconnection205 without occlusion by the presence of thecathode connector piece37. The arrangement also reinforces the area ofports44,44′ to facilitate precise drilling of theholes44,44′.
Air Inlets and Control of Resistance to Draw
• In the preferred embodiment, at least oneair inlet44 is formed in theouter tube6, preferably adjacent the threadedconnection205 to minimize the chance of a smoker' fingers occluding one of the ports and to control the resistance to draw (RTD) during smoking. Preferably, each of the RTD controlling,air inlets44 and44′ are machined into thecasing6 with precision tooling such that their diameters are closely controlled and replicated from onecigarette60 to the next during their manufacture. Preferably, theair inlets44 and44′ are drilled with carbide drill bits or other high-precision tools and/or techniques. Also preferably, theouter tube6 is formed of metal or metal alloys such that the size and shape of theair inlets44,44′ is not altered during manufacturing operations, packaging and smoking. Thus, theair inlets44,44′ provide consistent RTD. In the preferred embodiment, theair inlets44,44′ are sized and configured such that theelectronic cigarette60 has a RTD in the range of from about 60 mm H₂O to about 150 mm H₂O, more preferably about 90 mm H₂O to about 110 mm H₂O, most preferably about 100 mm H₂O to about 130 mm H₂O.
• The RTD controlling,air inlets44 and44′ are the critical orifice (i.e. the smallest orifice along the pathway from theair inlets44,44′ and theinner passage21 of the inner tube62 (where theheater14 aerosolizes liquid). Accordingly, theair inlets44 and44′ control the level of resistance to draw of thecigarette60, which may be set at a level that contributes a drawing experience similar to that of drawing upon a conventional, lit-end cigarette.
• Referring specifically toFIG. 1, another aspect of maintaining precise and reproducible resistance to draw is use of a metallic material in thecasing6 which is conducive to precision tooling and techniques. If another material is desired for the casing6 (such as a plastic for presenting a softer feel), theair inlets44,44′ may be instead formed in a metallic plate fixture (or insert)43 provided at the location of theair inlets44,44′ so as to maintain the precision of theair inlets44,44′.
• It is envisioned that themetallic plate insert43 may be included even in instances where thecasing6 is metallic, in that such arrangement allows theair inlets44,44′ to be produced and tested separately (off-line) on a collection of blank metallic plate inserts43. Advantageously, should any finished metallic plate inserts43 fail to meet standards or specifications for air inlet diameter (and RTD), the failed inserts may be disposed of instead of entire cartridge assemblies (first section)70.
• Referring back toFIG. 1, themetallic plate insert43 may comprise a separate piece that becomes affixed to an outer surface of thecasing6 or wholly within thecasing6, in which case theouter casing6 is preferably provided with an oversized hole, which can be superposed over the area of theair inlet44. It is also envisioned that the insert might be shaped and fitted flush with the contour of thecasing6, using a snap fit and/or adhesive between the insert and thecasing6 or entirely within (internal of the outer casing6). Preferably the shape and the location of theair inlet44 of theinsert43 has a symmetry such that theair inlet44 remains fully operative whether theinsert43 is positioned as shown inFIG. 1 or flipped 180 degrees. Moreover, themetallic plate insert43 can be provided on an inside surface or on an outside surface of theouter casing6. Themetallic plate insert43 can extend fully or partially about a circumference of thecigarette60. When themetallic plate insert43 extends partially about the circumference, multiple metallic plate inserts43 can be used, each metallic plate insert43 corresponding to asingle air inlet44,44′.
• In the preferred embodiment, thesecond section72, includes anair inlet45 at an upstream end5 of thecigarette60, which is sized just sufficient to assure proper operation of thepuff sensor16, located nearby. Drawing action upon themouth end insert8 is communicated to theair inlet port45 through central channels provided in theanode post47cof thefirst section70 and the anode connection post47bof thesecond section72 and alongspace13 between thebattery1 and the casing of thesecond section72. These channels and theport45 itself are sized such that the airflow rate there through are much smaller than through theair inlets44,44′, so that the impact on RTD is minimized and consistency in RTD is maintained. For example, each air inlet can be less than about 2.0 mm in width and less than about 1.5 mm in depth. For example, each air inlet can be about 0.7 mm to about 0.8 mm in width and about 0.7 mm to about 0.8 mm in depth. In a preferred embodiment, 95% of the air introduced in thecigarette60 is through theair inlets44,44′, whereas only 5% of the total air flow enters through theinlet45 at the upstream end5 of thecigarette60. Preferably, the ratio is determined by making acentral channel34 of theanode post47bof thesecond section72 small enough to impart a pressure drop far greater than that of theair inlets44,44′. For example, thecentral channel34 of theanode post47bmay be sized to impart a pressure drop of approximately 2000 mm water (in contrast to a nominal pressure drop of 100 mm water fromair inlets44,44′ combined).
• Referring toFIG. 19, in order to maintain consistent RTD in the product, a removableprotective covering601 can be applied to theair inlets44,44′ to prevent degradation from dirt and dings during, manufacture, packaging shipping and handling at retail and beyond as shown inFIG. 19. To maintain consistent RTD until consumption, a circumferential wrapping ortape601 may be wrapped about theouter casing6 at the locations of theair inlets44,44′. In the alternative or in addition, thecigarette60 may be accompanied with a reusable protective cover to provide the same or additional protections.
• In addition, current manufacturing techniques for electronic cigarettes can be modified to include testing for consistent RTD. In other words, there is a need to couple an understanding of how to achieve consistent RTD in the product (as taught above) with an understanding of how to test for it in the course of manufacturing the product (as taught in the following). Achieving consistent RTD from one electronic cigarette to the next promotes consistent performance and delivery levels, and enhances smoking experiences by meeting smoker's expectations that a draw upon an electronic cigarette will be akin to drawing upon a lit end cigarette or cigar. The latter may include testing metallic plate inserts43 prior to installation as previously described; or instead or in addition, testing completedfirst sections70 by fastening a nominal, but inactivatedsecond section72 to a newly producedfirst section70 to create a benign, inactive test configuration that accurately reproduces airflow event, but without risk of heater activation and applying a predetermined drawing action upon the configuration while measuring pressure drop. By way of non-limiting example, a fully assembled electronic cigarette may be drawn through the test configuration while pressure drop is measured using a PV10 pressure drop instrument manufactured by Borgwaldt KC of Chesterfield, Va. A suitable pressure drop testing method for electronic cigarettes can be adopted from standard method ISO 6565:2011 entitled “Tobacco and tobacco products—Draw Resistance of Cigarettes and Pressure Drop of Filter Rods—Standard Conditions and Measurement”, and applied with instrumentation capable of measure pressure drop in a working range of 50 mmWG (mm water gauge) to 1900 mmWG and a diameter range of 5.0 mm to 9.0 mm. The test can be completed in a matter of seconds and the instrumentation can be calibrated to a range of 50 mmWG to 300 mmWG.
• Instead of using an inactivatedsecond section72, it is envisioned that a releasable test body might be employed to serve the same purpose in a benign (inactive) test configuration. The test body would be configured to reproduce nominal impact of a real reusablesecond portion72 upon RTD, but could be optimized for machine handing and high speed automated coupling to and removal from newly producedfirst sections70 that are undergoing testing.
• The inclusion of a threadedconnection205 does not facilitate automated, high speed machine handling and execution of the RTD tests. Referring now toFIG. 12, analternative coupling205′ may includeconnections comprising pins501 andreleasable detents503 and/or electrical bearing surfaces505 with releasable detents, rotational locking devices or the like. In the illustrated embodiment, thedetent503 cooperates with a raised annulus509. In the alternative, one or more biased balls may be used in lieu of or in addition to the raised annulus509. Such arrangements facilitate automated machine handling, provide a greater capacity for speedy yet accurate testing of RTD, and facilitate machine automated execution of RTD testing. It is envisioned that quality control during the drilling of orifices could include a feedback loop such that the RTD test results are monitored to detect trends away from specifications so that corrective measures may be undertaken, such as replacement of a worn drill bit.
• Referring now toFIGS. 3aand3b, preferably, thecathode connector piece37 includes opposingnotches38,38′ about itsperimeter39, which, upon insertion of thecathode connector piece37 into theouter casing6, are aligned with the location of each of two or more RTD-controlling,air inlets44 and44′ in theouter casing6. In some embodiments, more than twoair inlets44,44′ may be included (e.g., three, four, five, six, seven, eight, nine, ten or more). Alternatively, asingle air inlet44 can be included. In an embodiment, such alignment may appear as shown inFIG. 3b. Such arrangement allows for placement of theair inlets44,44′ close to the threadedconnection205 without occlusion by the presence of thecathode connector piece37. The arrangement also reinforces the area ofair inlets44,44′, which can serve to facilitate precise drilling of theair inlets44,44′. Other arrangements can also be used as discussed below.
• In another embodiment, as shown inFIG. 13, thecathode connector piece37 can include one ormore slits300 formed in theperimeter39 of thecathode connector piece37. Theouter casing6 of thecartridge portion70 is slid over the unthreaded end of theconnector piece37 until it reaches the stop (or edge)307, leaving a predetermined portion of theslit300 open to the exterior of thecartridge portion70 for the admission of air. The admitted air can travel along theslit300 and into the interior of thecartridge portion70. Theslit300 may be used as the critical orifice and can be used in lieu ofair inlets44 and44′. In another embodiment, theslit300 may be used in addition toair inlets44 and44′.
• In yet another embodiment, as shown inFIGS. 14A,14B and14C, thecathode connector piece37 can include one or moreangled holes301 formed therein, which communicate with one ormore slots302 in acathode connection fixture49b. Preferably, thecathode connection fixture49bcan include an emptyannular space303 in an inner portion thereof which communicates with the one ormore slots302. Air is drawn in throughslot302 and travels into theannular space303 and from there into theangled holes307. Thus, there is no need to line up theslot302 with theangled hole301 because air will travel around theannular space303 and into theangled holes301 even if theholes301 andslots302 are not aligned. This arrangement provides advantages during manufacture since theangled holes301 need not be aligned with theslots302.
• As shown inFIG. 15, in yet another embodiment, theanode post47ccan be shortened as compared to theanode post47cofFIG. 2 so as to provide a larger air gap behind thecathode connector piece37. Air enters viaslot302′ (not shown inFIG. 15 other than its relative position) and is drawn through aninternal air inlet44 viaannular space303 and then flows straight into the air gap, through thecentral channel34 of theanode post47cand into thecentral channel20 leading to theheater14.
Liquid Supply Region, Heater and Wick
• Preferably, anose portion93 of andownstream gasket10 is fitted into adownstream end portion81 of theinner tube62. Anouter perimeter82 of thegasket10 provides a substantially liquid-tight seal with aninterior surface97 of theouter casing6. Thedownstream gasket10 includes acentral channel84 disposed between thecentral passage21 of theinner tube62 and the interior of themouth end insert8 and which communicates aerosol from thecentral passage21 to themouth end insert8.
• The space defined between thegaskets10 and15 and theouter tube6 and theinner tube62 establish the confines of aliquid supply region22. Theliquid supply region22 comprises a liquid material and optionally aliquid storage medium210 operable to store the liquid material therein. Theliquid storage medium210 may comprise a winding of cotton gauze or other fibrous material about theinner tube62.
• In the preferred embodiment, theliquid supply region22 is contained in an outer annulus620 betweeninner tube62 andouter tube6 and between thegaskets10 and15. Thus, theliquid supply region22 at least partially surrounds thecentral air passage21. Theheater14 extends transversely across thecentral channel21 between opposing portions of theliquid supply region22.
• Preferably, theliquid storage medium210 is a fibrous material comprising cotton, polyethylene, polyester, rayon and combinations thereof. Preferably, the fibers have a diameter ranging in size from about 6 microns to about 15 microns (e.g., about 8 microns to about 12 microns or about 9 microns to about 11 microns). Theliquid storage medium210 can be a sintered, porous or foamed material. Also preferably, the fibers are sized to be irrespirable and can have a cross-section which has a y shape, cross shape, clover shape or any other suitable shape. In the alternative, theliquid supply region22 may comprise a filled tank lacking afibrous storage medium21 and containing only liquid material.
• Also preferably, the liquid material has a boiling point suitable for use in theelectronic cigarette60. If the boiling point is too high, theheater14 will not be able to vaporize liquid in thewick28. However, if the boiling point is too low, the liquid may vaporize even when theheater14 is not being activated.
• Preferably, the liquid material includes a tobacco-containing material including volatile tobacco flavor compounds which are released from the liquid upon heating. The liquid may also be a tobacco flavor containing material or a nicotine-containing material. Alternatively, or in addition, the liquid may include a non-tobacco material. For example, the liquid may include water, solvents, ethanol, plant extracts and natural or artificial flavors. Preferably, the liquid further includes an aerosol former. Examples of suitable aerosol formers are glycerine and propylene glycol.
• Referring now also toFIG. 8, in use, liquid material is transferred from theliquid supply region22 and/orliquid storage medium210 in proximity of the 14 heater by capillary action of thewick28. In one embodiment, thewick28 has afirst end portion29 and asecond end portion31 as shown inFIG. 8. Thefirst end29 and thesecond end31 extend into opposite sides of theliquid storage medium21 for contact with liquid material contained therein. Also preferably, theheater14 at least partially surrounds acentral portion113 of thewick28 such that when theheater14 is activated, the liquid in thecentral portion113 of thewick28 is vaporized by theheater14 to form an aerosol. Thewick28 preferably comprises filaments having a capacity to draw a liquid, more preferably a bundle of glass (or ceramic) filaments and most preferably a bundle comprising a group of windings of glass filaments, preferably three of such windings, all which arrangements are capable of drawing liquid via capillary action via interstitial spacings between the filaments. Preferably, thewick28 is flexible and includes three strands, each strand including a plurality of filaments. Moreover, it is noted that the end portions of the 29 and 31 of thewick28 are flexible and foldable into the confines of theliquid supply region22.
• Advantageously, the liquid material in theliquid supply region22 is protected from oxygen (because oxygen cannot generally enter theliquid supply region22 via the wick28). In some embodiments, the liquid material is also protected from light so that the risk of degradation of the liquid material is significantly reduced. Thus, a high level of shelf-life and cleanliness can be maintained.
• In the preferred embodiment, theliquid supply region22 is sized and configured to hold enough liquid material such that theelectronic cigarette60 is operable for smoking for at least about 200 seconds, preferably at least about 250 seconds, more preferably at least 300 seconds and most preferably at least about 350 seconds. Thus,liquid supply region22 is equivalent to about one pack of traditional cigarettes. Moreover, theelectronic cigarette60 can be configured to allow each puff to last a maximum of about 5 seconds.
Mouth End Insert
• Referring toFIGS. 2,3a,4,5,6,7 and17, thefirst section70 includes amouth end insert8 having at least two diverging outlet passages24 (e.g., preferably 2 to 6outlet passages24, more preferably 4 outlet passages24). Preferably, theoutlet passages24 are located off-axis and are angled outwardly in relation to thecentral channel21 of the inner tube62 (i.e., divergently). Also preferably, the mouth end insert (or flow guide)8 includesoutlets24 uniformly distributed about the perimeter ofmouth end insert8 so as to substantially uniformly distribute aerosol in a smoker's mouth during use and create a greater perception of fullness in the mouth. Thus, as the aerosol passes into a smoker's mouth, the aerosol enters the mouth and moves in different directions so as to provide a full mouth feel. In contrast, electronic cigarettes having a single, on-axis orifice tend to direct its aerosol as single jet of greater velocity toward a more limited location within a smoker's mouth.
• In addition, the divergingoutlet passages24 are arranged and includeinterior surfaces83 such that droplets of unaerosolized liquid material, if any, that may be entrained in the aerosol impact theinterior surfaces83 of themouth end insert8 and/or impact portions ofwalls305 which define the divergingoutlet passages24. As a result such droplets are substantially removed or broken apart, to the enhancement of the aerosol.
• In the preferred embodiment, the divergingoutlet passages24 are angled at about 5° to about 60° with respect to the longitudinal axis of theouter tube6 so as to more completely distribute aerosol throughout a mouth of a smoker during use and to remove droplets. In a preferred embodiment, there are four divergingoutlet passages24 each at an angle of about 40° to about 50° with respect to the longitudinal axis of theouter tube6, more preferably about 40° to about 45° and most preferably about 42°.
• Preferably, each of the divergingoutlet passages24 has a diameter ranging from about 0.015 inch to about 0.090 inch (e.g., about 0.020 inch to about 0.040 inch or about 0.028 inch to about 0.038 inch). The size of the divergingoutlet passages24 and the number of divergingoutlet passages24 can be selected to adjust the resistance to draw (RTD) of theelectronic cigarette60, if desired.
• In one embodiment shown inFIG. 17, themouth end insert8 can include divergingoutlet passages24 and an on-axis outlet passage26.
• As shown inFIG. 2, aninterior surface83 of themouth end insert8 can comprise a generallydomed surface83. Alternatively, as shown inFIG. 7, the annularinterior surface83′ of themouth end insert8 can be generally cylindrical or frustoconical, with a planar end surface. Preferably, theinterior surface83 is substantially uniform over the surface thereof. Moreover, theinterior surface83 can be symmetrical about the longitudinal axis of themouth end insert8. However, in other embodiments, theinterior surface83 can be irregular and/or have other shapes.
• In a preferred embodiment, a hollow911 is disposed at the convergence of the divergingoutlet passages24 within themouth end insert8
• Themouth end insert8 may be integrally affixed within thetube6 of thecartridge70.
• As mentioned previously, the multi-portmouth end insert8 disperses and changes the direction of the aerosol as it is drawn from theelectronic cigarette60 so as to provide a fuller mouth feel. As aerosol is formed, it passes through thecentral channel21 in theinner tube62 and through thecentral channel84 in thedownstream gasket10. In panel testing of early prototypes, some panelists reported a “hot” sensation on the lips from smoking an electronic cigarette constructed to include a mouth end insert including a plurality of divergingoutlet passages24 and acentral channel84 having a diameter of about 1.3 mm. However, in electronic cigarettes in which the inside diameter of thecentral channel84 was increased to about 2.6 mm, reports of “hot” sensations essentially ceased.
• Dynamic modeling of the area at and about thedownstream gasket10 and themouth end insert8 has indicated that a small 1 mm widecentral channel84 at thegasket10 tends to create peak velocities of approximately 12 meters per second (m/sec) in aerosol exiting the mouth end insert. In contrast, modeling of a system including a 5 mm widecentral channel84 indicates peak velocities of only 2.5 m/s is achieved at the exits of the divergingoutlet passages24 of themouth end insert8, which is approximately a five-fold decrease in air velocity. From the aforementioned testing and modeling it is believed a further improvement in the organoleptic experience with an electronic cigarette is achieved by preventing acceleration of the aerosol flow stream by increasing the diameter of thecentral channel84 before it is drawn through the exits of the divergingoutlet passages24 of the multi-portmouth end insert8.
• Accordingly, it is advantageous to provide an electronic cigarette having adownstream gasket10 having acentral channel84, which has a diameter sufficient to prevent acceleration of the aerosol flow stream before reaching themouth end insert8. Preferably, the diameter of thecentral channel84 is about 2.0 mm to about 3.0 mm, more preferably about 2.4 mm to about 2.8 mm. Themouth end insert8 then divides output from thecentral channel84 into multiple divergent streams of reduced speed so as to provide a full mouth feel and to avoid sensations of “hot”.
• In that an appropriately sizedcentral channel84 of thegasket10 serves to substantially prevent acceleration of the aerosol, such functionality can be further enhanced by providing the exit orifice with a beveled rim (not shown) at its exit plane to further reduce speed of the aerosol before it reaches themouth end insert8.
• In an alternative embodiment, themouth end insert8 and thedownstream gasket10 can be integrally formed as a single piece so as to enhance consistent performance and to facilitate manufacture.
• As shown inFIGS. 10 and 11, in an alternative embodiment, theelectronic cigarette60 ofFIG. 1 can include amouth end insert8 having astationary piece27 and arotatable piece25.Outlets24,24′ are located in each of thestationary piece27 and therotatable piece25. Theoutlets24,24′ match up as shown to allow aerosol to enter a smoker's mouth. However, therotatable piece25 can be rotated within themouth end insert8 so as to at least partially block one or more of theoutlets24 in the stationarymouth end insert28. Thus, the consumer can adjust the amount of aerosol drawn with each puff. Theoutlets24,24′ can be formed in the mouth end insertmouth end insert8 such that theoutlets24,24′ diverge to provide a fuller mouth feel during inhalation of the aerosol.
Circuitry, Alloys Improving Consistent Heater Performance, Hot Spots and Carbonyl Abatement
• In the preferred embodiment, thepower supply1 includes a battery arranged in theelectronic cigarette60 such that theanode47ais downstream of thecathode49a. Abattery anode post47bof thesecond section72 preferably contacts thebattery anode47a.
• More specifically, electrical connection between theanode47aof thebattery1 and theheater coil14 in thefirst section70 is established through a battery anode connection post47bin thesecond section72 of theelectronic cigarette60, ananode post47cof thecartridge70 and anelectrical lead47dconnecting a rim portion of theanode post47cwith anelectrical lead109 of the heater element14 (seeFIG. 8). Likewise, electrical connection between thecathode49aof thebattery1 and theother lead109′ of theheater coil14 is established through the threadedconnection205 between acathode connection fixture49bof thesecond portion72 and thecathode connector piece37 of thefirst section70 and from there through anelectrical lead49cwhich electrically connects thefixture37 to theopposite lead109′ of theheater coil14.
• Preferably, the electrical leads47d,49cand the heater leads109,109′ are highly conductive and temperature resistant while thecoiled section110 of theheater14 is highly resistive so that heat generation occurs primarily along thecoils110 of theheater14. Also preferably, theelectrical lead47dis connected to theheater lead109 by crimping. Likewise, theelectrical lead49cis connected to theheater lead109′ by crimping. In an alternative embodiment, the electrical leads47d,49ccan be attached to the heater leads109,109′ via soldering. Crimping is preferred as it speeds manufacture.
• The battery can be a Lithium-ion battery or one of its variants, for example a Lithium-ion polymer battery. Alternatively, the battery may be a Nickel-metal hydride battery, a Nickel cadmium battery, a Lithium-manganese battery, a Lithium-cobalt battery or a fuel cell. In that case, preferably, theelectronic cigarette60 is usable by a smoker until the energy in the power supply is depleted or in the case of lithium polymer battery, a minimum voltage cut-off level is achieved.
• Alternatively, thepower supply1 may be rechargeable and include circuitry allowing the battery to be chargeable by an external charging device. In that case, preferably the circuitry, when charged, provides power for a pre-determined number of puffs, after which the circuitry must be re-connected to an external charging device. To recharge theelectronic cigarette60, an USB charger or other suitable charger assembly can be used.
• Preferably, theelectronic cigarette60 also includes control circuitry including apuff sensor16. Thepuff sensor16 is operable to sense an air pressure drop and initiate application of voltage from thepower supply1 to theheater14. As shown inFIG. 2, the control circuitry can also include aheater activation light48 operable to glow when theheater14 is activated. Preferably, theheater activation light48 comprises an LED and is at an upstream end of theelectronic cigarette60 so that theheater activation light48 takes on the appearance of a burning coal during a puff. Moreover, theheater activation light48 can be arranged to be visible to the smoker. In addition, theheater activation light48 can be utilized for cigarette system diagnostics or to indicate that recharging is in progress. The light48 can also be configured such that the smoker can activate and/or deactivate the light48 for privacy, such that the light48 would not activate during smoking if desired.
• Preferably, the at least one air inlet45 (FIG. 1) is located adjacent thepuff sensor16, such that thepuff sensor16 senses air flow indicative of a smoker taking a puff and activates thepower supply1 and theheater activation light48 to indicate that theheater14 is working.
• A control circuit is preferably integrated with thepuff sensor16 and supplies power to theheater14 responsive to thepuff sensor16, preferably with a maximum, time-period limiter.
• Alternatively, the control circuitry may include a manually operable switch for a smoker to initiate a puff. The time-period of the electric current supply to the heater may be pre-set depending on the amount of liquid desired to be vaporized. Alternatively, the circuitry may supply power to theheater14 as long as thepuff sensor16 detects a pressure drop.
• Preferably, when activated, theheater14 heats a portion of thewick28 surrounded by the heater for less than about 10 seconds, more preferably less than about 7 seconds. Thus, the power cycle (or maximum puff length) can range in period from about 2 seconds to about 10 seconds (e.g., about 3 seconds to about 9 seconds, about 4 seconds to about 8 seconds or about 5 seconds to about 7 seconds).
• Preferably, theheater14 is a wire coil that surrounds thewick28. Examples of suitable electrically resistive materials include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium-titanium-zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel. For example, the heater can be formed of nickel aluminide, a material with a layer of alumina on the surface, iron aluminide and other composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. Preferably, theheater14 comprises at least one material selected from the group consisting of stainless steel, copper, copper alloys, nickel-chromium alloys, super alloys and combinations thereof. In a preferred embodiment, theheater14 is formed of nickel-chromium alloys or iron-chromium alloys, although the latter is not preferred for reasons which follow. In another embodiment, theheater14 can be a ceramic heater having an electrically resistive layer on an outside surface thereof.
• In another embodiment, theheater14 may be constructed of an iron-aluminide (e.g., FeAl or Fe₃Al), such as those described in commonly owned U.S. Pat. No. 5,595,706 to Sikka et al. filed Dec. 29, 1994, or nickel aluminide (e.g., Ni₃Al). Use of iron-aluminide is advantageous in that iron-aluminide exhibits high resistivity. FeAl exhibits a resistivity of approximately 180 micro-ohms, whereas stainless steel exhibits approximately 50 to 91 micro-ohms. The higher resistivity lowers current draw or load on the power source (battery)1.
• In the preferred embodiment, theheater coil14 is formed from a nickel-chromium alloy that is essentially free of iron content. Experience has indicated that heater coils constructed from an iron chromium alloy suffered oxidation of their iron content if the alloys were contacted with water during manufacturing operations, during shelf-life and/or operation of the device.
• It is known that heating glycerin and/or propylene glycol beyond certain temperatures produces carbonyls (which include formaldehydes). Iron oxide tends to catalyze these reactions such that carbonyls are produced at lower temperatures. By using alloys essentially free of iron content, such catalyzation is avoided and the possibility of producing carbonyls and other constituents is minimized.
• Moreover, in the manufacture and design of the preferred embodiment, certain aspects and measures are employed to avoid occurrence of unintended “hot spots” in theheater coil14 during its heating cycle. Hot spots may contribute excessive peak temperatures that may produce undesired constituents that would otherwise be avoided in the absence of a hot spot.
• While not wishing to be bound by theory, it is believed that if a winding of acoil heater14 is altered such that spacing between loops of thecoil14 is locally reduced, the reduced spacing will create hotspots that are believed to drive peak temperatures beyond desirable levels. It is also believed that establishing uniform spacing along the coils of theheater14 and taking steps to preserve the original, uniform spacing in the winding of thecoil heater14 will avoid the consequences of “hot spots”.
• In particular and referring toFIG. 8, it is envisioned that production ofconsistent coil spacing111 throughout thecoiled section110 of a givenheater coil14 may be achieved in ways including using automated winders to wind the coil about thewick28 and using thewick28 as an arbor for the winding step. In the preferred embodiment 3 to 8 windings are preferred, more preferably, 3 to 5 windings.
• Once established, the uniformity of thecoil spacing111 is preserved in the course of manufacture and in the design of the preferred embodiment.
• Referring also toFIG. 9A, in particular, the provision of opposingslots63 in theinner tube62 facilitates placement of theheater14 andwick28 into position within theinner tube62 without impaction between edges of theslots63 and the coiled section110 (shown inFIG. 8) of theheater14. Accordingly, edges of theslots63 are not allowed to impact and alter thecoil spacing111 of theheater14, which would otherwise create potential sources of hotspots.
• Referring now toFIG. 9B, care is taken to position aclosure ring69 such that it is proximate to or touches but does not urge against thewick28. Such positioning avoids imposing bending moments upon theheater coil14 and avoids bowing of thecoil14 which might otherwise produce hotspots along one side of thecoil14 where thecoil spacing111 would become compressed and reduced. Thus, the upstream edge114 of theclosure ring69 is brought into proximity of thewick28, but is not positioned over thewick28 so as to avoid the possibility of the aforementioned bowing effect. Theclosure ring69, when placed as shown inFIG. 9B, closes off a remainder of open space provided between the heater coil assembly and theslot63.
• In the preferred embodiment, theinner tube62 and theclosure ring69 are constructed from woven fiberglass.
• In the preferred embodiment, theinner tube62 has a diameter of about 4 mm and each of the opposingslots63 has major and minor dimensions of about 2 mm by about 4 mm.
• In one embodiment, theheater14 comprises a wire coil which at least partially surrounds thewick28. In that embodiment, preferably the wire is a metal wire and/or the heater coil may extend fully or partially along the length of thewick28. Theheater coil14 may extend fully or partially around the circumference of thewick28. In another embodiment, the heater coil is not in contact with thewick28.
• Preferably, theheater14 heats liquid in thewick28 by thermal conduction. Alternatively, heat from theheater14 may be conducted to the liquid by means of a heat conductive element or theheater14 may transfer heat to the incoming ambient air that is drawn through theelectronic cigarette60 during use, which in turn heats the liquid by convection.
• In one embodiment, thewick28 comprises a ceramic wick of ceramic filaments having a capacity to draw a liquid. As noted above, thewick28 is at least partially surrounded by theheater14. Moreover, in the preferred embodiment, thewick28 extends through opposedslots63 in theinner tube62 such that each end of thewick28 is in contact with the liquid supply region22 (shown inFIG. 2).
• In the preferred embodiment, thewick28 comprises filaments and comprises a bundle of glass filaments. For example, thewick28 may include a plurality of filaments. The filaments or threads may be generally aligned in a direction perpendicular (transverse) to the longitudinal direction of the electronic cigarette. Preferably, thewick28 includes 1 to 8 filaments, more preferably 2 to 6 filaments. In the preferred embodiment, thewick28 includes 3 stands, each strand comprising a plurality of glass filaments twisted together.
• In the preferred embodiment, the structure of thewick28 is formed of filaments through which the liquid can be transported to theheater14 by capillary action. Thewick28 can include filaments having a cross-section which is generally cross-shaped, clover-shaped, Y-shaped or in any other suitable shape.
• Preferably, thewick28 includes any suitable material or combination of materials. Examples of suitable materials are glass, ceramic- or graphite-based materials. Moreover, thewick28 may have any suitable capillarity drawing action to accommodate aerosol generating liquids having different liquid physical properties such as density, viscosity, surface tension and vapor pressure. The capillary properties of thewick28, combined with the properties of the liquid, ensure that thewick28 is always wet in the area of theheater14 to avoid overheating of theheater14.
• Instead of using awick28, theheater14 can be a porous material which incorporates a resistance heater formed of a material having a high electrical resistance capable of generating heat quickly.
• Preferably, thewick28 and the fibrous medium of theliquid supply region22 are constructed from glass fiber.
Sleeve Assembly
• As shown inFIG. 18, theelectronic cigarette60 can also include asleeve assembly87 removably and/or rotatably positioned about afirst section70 of theelectronic cigarette70. Moreover, thesleeve assembly87 insulates at least a portion of thefirst section70 so as to maintain the temperature of the aerosol prior to delivery to the smoker. In the preferred embodiment, thesleeve assembly87 is rotatable about theelectronic cigarette60 and includes spaced apart slots88 arranged transversely about the sleeve assembly such that the slots88 line up with theair inlets44,44′ in thefirst section70 to allow air to pass into theelectronic cigarette60 when a smoker draws a puff. Before or during smoking, the smoker can rotate thesleeve assembly87 such that theair inlets44,44′ are at least partially blocked by thesleeve assembly87 so as to adjust the resistance to draw and/or ventilation of theelectronic cigarette60 if desired.
• Preferably, thesleeve assembly87 is made of silicone or other pliable material so as to provide a soft mouthfeel to the smoker. However, thesleeve assembly87 can be formed in one or more pieces and can be formed of a variety of materials including plastics, metals and combinations thereof. In a preferred embodiment, thesleeve assembly87 is a single piece formed of silicone. Thesleeve assembly87 can be removed and reused with other electronic cigarettes or can be discarded along with thefirst section70. Thesleeve assembly87 can be any suitable color and/or can include graphics or other indicia.
Aroma Delivery
• As shown inFIG. 11, theelectronic cigarette60 can also include anaroma strip89 located on anouter surface91 of at least one of thefirst section70 and thesecond section72. Alternatively, thearoma strip89 can be located on a portion of thesleeve assembly87. Preferably, thearoma strip89 is located between the battery of the device and theheater14 such that thearoma strip89 is adjacent a smoker's nose during smoking. Thearoma strip89 can include a flavor aroma gel, film or solution including a fragrance material that is released before and/or during smoking. In one embodiment, the flavor aroma of the gel, fluid and/or solution can be released by the action of a puff which may open a vent over the aroma strip when positioned inside the first section70 (not shown). Alternatively, heat generated by theheater14 can cause the release of the aroma.
• In one embodiment, thearoma strip89 can include tobacco flavor extracts. Such an extract can be obtained by grinding tobacco material to small pieces and extracting with an organic solvent for a few hours by shaking the mixture. The extract can then be filtered, dried (for example with sodium sulfate) and concentrated at controlled temperature and pressure. Alternatively, the extracts can be obtained using techniques known in the field of flavor chemistry, such as the Solvent Assisted Flavor Extraction (SAFE) distillation technique (Engel et al. 1999), which allows separation of the volatile fraction from the non-volatile fraction. Additionally, pH fractionation and chromatographic methods can be used for further separation and/or isolation of specific compounds. The intensity of the extract can be adjusted by diluting with an organic solvent or water.
• Thearoma strip89 can be a polymeric or paper strip to which the extract can be applied, for example, using a paintbrush or by impregnation. Alternatively, the extract can be encapsulated in a paper ring and/or strip and released manually by the smoker, for example by squeezing during smoking the aroma strip.
• In one embodiment, theelectronic cigarette60 ofFIGS. 2,5,7 and9 can also include a filter segment upstream of theheater14 and operable to restrict flow of air through theelectronic cigarette60. The addition of a filter segment can also aid in adjusting the resistance to draw.
• When the word “about” is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated numerical value. Moreover, when reference is made to percentages in this specification, it is intended that those percentages are based on weight, i.e., weight percentages.
• Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. When used with geometric terms, the words “generally” and “substantially” are intended to encompass not only features which meet the strict definitions but also features which fairly approximate the strict definitions.
• It will now be apparent that a new, improved, and nonobvious electronic cigarette has been described in this specification with sufficient particularity as to be understood by one of ordinary skill in the art. Moreover, it will be apparent to those skilled in the art that numerous modifications, variations, substitutions, and equivalents exist for features of the electronic cigarette which do not materially depart from the spirit and scope of the invention. Accordingly, it is expressly intended that all such modifications, variations, substitutions, and equivalents which fall within the spirit and scope of the invention as defined by the appended claims shall be embraced by the appended claims.

Claims (16)

We claim:

1. A method of manufacturing an electronic smoking article wherein a wick is surrounded by a coil heater such that the wick delivers liquid material to the coil heater and the coil heater heats the liquid material to a temperature sufficient to vaporize the liquid material and form an essentially carbonyl free aerosol, the method comprising:

forming a heater coil about a wick, the forming step including establishing coil windings having substantially uniform spacing between each winding; and

maintaining the spacing during manufacture of the electronic smoking article.

2. The method ofclaim 1 wherein the maintaining step includes providing clearance for the coil windings when inserting the heater coil in an inner tube extending in a longitudinal direction within the electronic smoking article.

3. The method ofclaim 2, wherein the maintaining step further includes placing a closure ring proximate to the wick to at least partially close said clearance, the placing step being completed essentially without imparting a bending moment upon the heater coil.

4. An electronic smoking article comprising:

an outer tube extending in a longitudinal direction;

an inner tube within the outer tube, the inner tube including a pair of opposing slots;

a liquid supply comprising a liquid material, the liquid supply contained in an outer annulus between the outer tube and the inner tube;

a coil heater located in the inner tube, end portions of the coil heater extending through the opposing slots in the inner tube, the coil heater being formed of an iron-free alloy and having substantially uniformly spaced windings in an essentially unbowed condition;

a wick in communication with the liquid supply and surrounded by the coil heater such that the wick delivers liquid material to the coil heater and the coil heater heats the liquid material to a temperature sufficient to vaporize the liquid material and form an aerosol in the inner tube; and

a mouth end insert at a mouth end of the outer tube.

5. The electronic smoking article ofclaim 4, wherein each of the opposing slots has dimensions sufficient to provide clearance between inner peripheries of the slots and the coil heater.

6. The electronic smoking article ofclaim 5, wherein the inner tube has a diameter of about 4 mm and each of the opposing slots has major and minor dimensions of about 2 mm by about 4 mm.

7. The electronic smoking article ofclaim 4, wherein the electronic smoking article comprises a first section attachable to a second section and wherein the wick, the liquid supply and the mouth end insert are contained in the first section and a power supply connectable to leads of the coil heater and operable to apply voltage across the coil heater is contained in a second section.

8. The electronic smoking article ofclaim 4, further including a closure ring including an edge at an upstream end thereof, the closure ring being positioned such that the edge is proximate to portions of the wick outside the inner tube, the closure ring being operable to close portions of the opposing slots in the inner tube.

9. The electronic smoking article ofclaim 8, wherein said closure ring is positioned relative to the portions of the wick and the coil heater remains essentially in an unbowed condition.

10. The electronic smoking article ofclaim 4, wherein the electronic smoking article comprises a single outer tube and wherein the wick, the liquid supply, the mouth end insert and a power supply connected to the coil heater and operable to apply voltage across the coil heater are contained in the outer tube.

11. The electronic smoking article ofclaim 8, wherein the inner tube and the closure ring are each of woven fiberglass material.

12. The electronic smoking article ofclaim 4, wherein the coil heater comprises 3 to 8 uniformly spaced windings.

13. The electronic smoking article ofclaim 4, wherein the coil heater is formed of an iron-free, chromium alloy.

14. The electronic cigarette ofclaim 4, wherein the coil heater is formed of an iron-free, nickel chromium alloy.

15. An electronic smoking article comprising:

an outer tube extending in a longitudinal direction;

an inner tube within the outer tube, the inner tube including a pair of opposing slots;

a liquid supply comprising a liquid material, the liquid supply contained in an outer annulus between the outer tube and the inner tube;

a coil heater located in the inner tube, end portions of the coil heater extending through the opposing slots in the inner tube, the coil heater being formed of an iron-free alloy and having substantially uniformly spaced windings in an essentially unbowed condition;

a wick in communication with the liquid supply and surrounded by the coil heater such that the wick delivers liquid material to the coil heater and the coil heater heats the liquid material to a temperature sufficient to vaporize the liquid material and form an aerosol in the inner tube;

a mouth end insert at a mouth end of the outer tube;

a closure ring including an edge at an upstream end thereof, the closure ring being positioned such that the edge is proximate to portions of the wick outside the inner tube, the closure ring being operable to close portions of the opposing slots in the inner tube,

wherein said closure ring is positioned relative to the portions of the wick and the coil heater remains essentially in an unbowed condition, and

wherein each of the opposing slots has dimensions sufficient to provide clearance between inner peripheries of the slots and the coil heater.

16. A method of abating carbonyls in the output of an electronic smoking article comprising:

forming a heater coil about a wick, the forming step including establishing coil windings having substantially uniform spacing between each winding and using an essentially iron-free chromium alloy;

maintaining the spacing during manufacture of the electronic smoking article; and

maintaining the coil windings in an unbowed condition during manufacture of the electronic smoking article.

Images